Computing device



'J. THOMAS.

COMPUTING DEVICE. APPLICATION FILED NOV. 22, mm

Patented June 21, 1921.

W Y Gum,

UNITED STATES PATENT. OFFICE.

Y MS, OF PITTSBURG, KANSAS, ASSIGNOR TO- MORSE TWIST DRILL MACHINECOMPANY, OF NEW BEDFORD, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

COMPUTING DEVICE.

Specification of Letters Patent. Pate t d J e 21 1 2 Application filedNovember 22, 1919. Serial No. 840,026.

To allwhomitmay co'rwem:

Be it known that 1, JAMES THOMAS, a citizen of the United States, andresident of Pittsburg, in the county of Crawford and State of Kansas,have inventedv certain new and useful Improvements in Computing Devices,of which the following is a specification.

This invention relates to an instrument or device which is employed forcomputing numbers; and the object of this invention is to provide asimple and inexpensive instrument which can be conveniently manipulatedfor the purpose of accurately adding cooperate with the counter member.

Fig. 4 is an enlarged edge view showing one of the counter-operatingfingers in position beneath the rotatable disk and engag ingjherotatable counter.

ig. 5 is an enlarged fragmentary view of a modification of theinvention. Referring to the drawings, 10 designates a supporting base orback-plate which may be made of any-suitable, rigid material such aswood, cardboard or the like. The face or upper plate 11" of this deviceis preferably formed of celluloid or other transparent ma terial, thesamebeing provided-with a semicircular slot 12 formed through, itssurface.

Beneath this face-plate is another plate or sheet 13 having an annularslot 13" therein of substantially the same radius as the semi circularslot 12, and lying beneath it. On the 'outer face of said plate 13 and,preferably, on the outer side of the slot 13 ispro- ,vided a circulargraduation 13. This gradnation, consisting of two duplicate scales, m

and 3 progressively extending from opposite sides of a settin point 30,at one end of the semi-circular. s 013 12, to the other end served).

of the said slot 12. The scale 3 adjacent the slot 12 1s what is termeda calculating scale (as the calculations are made with this scale), andthe scale a: on the opposite side of theslot is what is termed anindicating scale. as the fractional results of the addit1on is lndicatedthereon, as will be later ob- Beneath this,gr'aduated plate. 13 I haverotatably mounted a disk 14 on the pivot pin 15,-wh1ch d1sk is providedwith a series of holes "16 formed on a circle whose radius issubstantially that of the slot 12 in the outer plate, said holes beingfor the purpose of receiving the point of an operating instrument 19such as a pencil or the like as shown in dotted lines in Fig. 2, wherebythe disk may be rotated and these holes are spaced apart so as toregister with the numbered .graduations on the member 13.. Two holes 17and 18 are formed on thedisk on diametrically opposlte sides of thecircle and are marked Zero to designate the starting positions of thedisk; that is, when starting a computation these zeros 17 and 18 must beat opposite ends of the slot 12, respectively, one lying opposite thesetting point 30.

In order that the device may be capable I of adding fractions amountingto more than a whole number, I have provided a counter 20 which is inthe form of a disk pivoted at 21 and is provided with teeth orprojections 22 on its periphery whereby when the disk 14 has made aone-half revolution, a fingermember 23 on the disk opposite one of thezero points engages the teeth of this counter and rotates it one tooth,thereby causing it to indicate the whole number through .the opening 24in the outer plate. There is a finger member 23 opposite each of thezero points or indicators 17 and 18.

Another opening 25 has been formed in the face-plate through which the'point of a pencil'or other instrument 'may be inserted to engage theteeth of the counter and rotate it back to zero position ready foranother counting operation after having been operated. I

In operating my improved fraction computing device I set the two zeromarks 17 and 18 of the disk 14 at opposite ends of the slot 12 formed inthetop plate.- Now if I wish to add 5/8 and 49/64 together I'first placethe operating pointer in the hole opposite the 5/8 graduation and rotatethe disk downwardly until the pointer engages the end of the circularslot in the outer plate which acts as a stop, and the hole in which itengages is brought in radial alinement with the'zero point 30,preferably positioned at the lower end of said slot. I'then place thepointer in the hole. in the disk opposite the fraction 49/64 and againrotate the disk downwardly until the pointerengages the end of the slot,in the manner above stated. It will be noted that during this secondmovement the counter-operating finger 23 opposite the zero mark counter20 and in passing engages a tooth thereof and rotates the counter tobring the numeral 1 into position to be observed through the opening 24and the zero point 17 is passed along to the graduations on the lefthalf of the circle where it points to the fraction 25 /64, thus showingat a glance that the sum of 5/8 and 49/64 equals 1 25/64. If nowit isdesired to add 41/64 to this sum it is only necessary to place thepointer through the slot into the hole opposite to that fraction, thenby rotating the disk until the point brings up against the lower end ofthe slot, the second zero mark 18' with its counter-operating finger 23has passed the counter to the point 1/32 and as it passed the counterits finger 23 rotated the same one tooth bringing the numeral2 into viewthrough the opening 24, thus the sum of the three fractions equals 21/32.

To reset the device to normal it is only necessary to engage the teethof the counter through the opening 25 and rotate it back to show zerowhich is observed through the opening 24.

I then rotate the disk 14 so that the two b zeros 17 and 18 are at theends of the slot 12 when the device is ready for another calculation.

I have shown and described a transparent outer or top plate with aseparate sheet, card or member located beneath it carrying the numberedgraduations, but I do not wish to be restricted to this particularconstruction, as the device may be made in the manner shown in Fig. 5 orany other suitable man-. ner which falls within the scope of the appended claims. In Fig. 5 the transparent plate 11 is dispensed with, buta projection 31, extending from the edge (if the plate 13, provides asuitable stop in lieu of the lower end of the slot 12, as will bereadily understood.

These different superimposed plates may be connected together by othersuitable fastenings.

The device is extremelysimple and ine'x- I pensive in construction andpractical and eflieient in its operation and by its use frac-.graduations 17 has passed the showing that rivets, pins or any I tionsmay be quickly added and the result accurately determined.

I claim:

1. A computing device of the character described comprising a platehaving numbered arranged in a circle thereon, sald graduationsconsisting of two duplicate scales progressively extending fromoppositesides of a setting point on the plate to a point opposite saidsetting point, a rotatable disk having graduations thereon spaced tocorrespond with said first graduation and to register therewith, saiddisk further having diametrically opposite indicators thereon, one ofwhich initially registers with said set ting point, the graduations onthe disk cooperating with one of said scales and said setting point inthe calculating operation, and said-indicators successively cooperatingwith the other of said scales to indicate the fractional results of thecalculation, counteroperating members on the disk, and a counter mountedon the device and actuated by said counter-operating members, when b aplurality of movements of said rotary disk in adding fractions, theresult is greater than a digit.

2. A computing device of the character described, comprising a backplate, a transparent face plate having a semi-circular slot formedtherethrough, numbered graduations arranged in a circle of substantiallythe radius of said slot, a rotatable disk having openings arranged tocoincide with said slot and to receive the point of an operatinginstrument and spaced to register with said graduations, said openingsbeing engageable through said slot, one end of said slot constituting asetting point and a stop engageable y the instrument for limiting eachcomputing movement of the disk, said disk further having diametricallyopposite indicators thereon to cooperate with the graduations forindicating certain results, and one of which indicators is to initiallyregister with said setting point, counter-operating fingers on saiddisk, a toothed rotatable counter adapted to be rotated by the passageof said fingers thereby, whereby a plurality of movements of said diskto add together two or more fractions, where the sum is equal to orgreater than a digit, causes said counter to be rotated to show thewhole number and the additional fractions being indicated on thegraduations by one of said indicators beyond said stop.

In testimony whereof I afiix in presenceof two witnesses.

JAMES THOMAS.

my signature Witnesses:

F. M. WETZEL, A. C. Sun.

